Heat transfer enhancement at generator stator core space blocks

Abstract

A ventilation pathway for a cooling gas to flow extends on a radial axis in a generator stator core. The ventilation pathway comprises at least two magnetic laminations and a plurality of space blocks extending radially in the generator stator core. The space blocks are fastened and disposed between the magnetic laminations. At least one of the space blocks includes a wavy longitudinal profile that includes an alternating pattern of peaks and valleys with respect to the radial axis of the generator stator core. Alternatively, at least one of the space blocks has a plurality of protrusions defining a pattern of peaks and valleys extending from a sidewall of the space block. Several different shapes of vortex generators are punched in the lamination are located within the ventilation pathway.

What is claimed is:  
     
       1. A generator stator core, comprising: 
       at least two laminations being adjacent; and  
       at least two space blocks extending on radially disposed between the laminations adapted to define a ventilation duct, wherein at least one space block includes a plurality of thermal roughness members disposed in a side surface of the at least one space block, the thermal roughness members being adapted to impart local flow disruptions in a fluid flowing along the side surface of the at least one space block for increasing the effective heat transfer coefficient.  
     
     
       2. The generator stator core in accordance with  claim 1 , wherein the thermal roughness members further comprises a plurality of thermal ribs being adjacent to each other. 
     
     
       3. The generator stator core in accordance with  claim 2 , wherein the thermal ribs are adapted for substantial bi-directional flow of the fluid towards the two laminations. 
     
     
       4. The generator stator core in accordance with  claim 2 , wherein the thermal ribs are adapted for substantial bi-directional flow of the fluid generally towards a central radial axis of the at the least one space block. 
     
     
       5. The generator stator core in accordance with  claim 2 , wherein the thermal ribs include at least one thermal rib having a first portion attached to opposing two ribs legs extending away from the first portion. 
     
     
       6. The generator stator core in accordance with  claim 2 , wherein the thermal ribs include at least one thermal rib having a raindrop shape construction. 
     
     
       7. The generator stator core in accordance with  claim 2 , wherein the thermal ribs includes at least one thermal ribs having an hemispherical construction. 
     
     
       8. The generator stator core in accordance with  claim 1 , wherein the least one space block or the other space block includes a thermal orifice adapted to allow the cooling to flow therethrough. 
     
     
       9. The generator stator core in accordance with  claim 1 , wherein the at least one space block include a wavy longitudinal profile. 
     
     
       10. The generator stator core in accordance with  claim 1 , further comprising a plurality of vortex generators disposed on at least one lamination, the vortex generators being adapted to impart vorties in the fluid flow. 
     
     
       11. The generator stator core in accordance with  claim 10 , wherein at least one of the vortex generators is selected from a group comprising a wedge shape, a hemispherical shape, a delta shape, and a raindrop shape. 
     
     
       12. The generator stator core in accordance with  claim 10 , wherein the vortex generators are disposed in a plurality of alternating rows on the least one lamination. 
     
     
       13. The generator stator core in accordance with  claim 1 , wherein said roughness members comprises a plurality of dimples. 
     
     
       14. The generator stator core in accordance with  claim 13 , wherein the dimples are raindrop shaped having a rounded end and an opposing pointed end, said pointed end being a downstream of the rounded end. 
     
     
       15. The generator stator core in accordance with  claim 13 , wherein the dimples are hemispherically shaped. 
     
     
       16. A generator stator core, comprising: 
       at least two laminations being adjacent; and  
       at least two space blocks being adjacent and extending on radially in the generator stator core, the space blocks being disposed between the laminations adapted to define a ventilation duct for a fluid to flow therethrough, wherein at least one of space blocks includes a plurality of thermal orifices disposed in a side surface of the space block and the thermal orifices being adapted to enable a portion of the fluid to flow therethrough from the ventilation duct.  
     
     
       17. The generator stator core in accordance with  claim 16 , wherein the at least one of the space blocks or the other space block includes a web member disposed between opposing flanges members, and a plurality of thermal roughness elements are disposed in the web member so as to provide flow disruptions in the fluid flowing in the ventilation duct. 
     
     
       18. The generator stator core in accordance with  claim 17 , wherein the thermal roughness elements comprise thermal ribs. 
     
     
       19. The generator stator core in accordance with  claim 16 , wherein thermal ribs are formed by a knurling process. 
     
     
       20. A space block for forming radially disposed ventilation ducts in a generator stator core, the space block comprising a sidewall having a heat transfer surface including a plurality of spaced ribs adapted to reduce a thickness of a boundary layer of the fluid flowing along the sidewall. 
     
     
       21. The space block in accordance with  claim 20 , wherein the each of die ribs comprise a general V-shape having an apex attached to a first leg and a second leg extending therefrom, the first leg and the second leg being disposed downstream of the apex with respect to a fluid flow direction along the space block. 
     
     
       22. The space block in accordance with  claim 21 , wherein the apex is coincident with a central radial axis of the space block, each of the first leg and the second leg being disposed at an angle with respect to the central radial axis. 
     
     
       23. The space block in accordance with  claim 22 , wherein the angle is between 45 degrees and 90 degrees. 
     
     
       24. The space block in accordance with  claim 20 , wherein the each of the ribs comprise a general V-shape having an apex attached to a first leg and a second leg extending therefrom, the first leg and the second leg being disposed upstream of the apex with respect to a fluid flow direction along the space block. 
     
     
       25. The space block in accordance with  claim 23 , wherein the ribs are generally web-shaped having a plurality of left oblique ribs and a plurality of right oblique ribs. 
     
     
       26. A generator stator core, comprising: 
       at least two laminations; and  
       a plurality of space blocks extending radially in the generator stator core, the space blocks being disposed between the laminations adapted to define a ventilation duct between adjacent space blocks fix a fluid to flow through, wherein at least one of the space blocks of the ventilation duct includes a knurled surface forming a non-planar surface profile for enhanced heat transfer to the fluid from the space block.  
     
     
       27. The generator stator core in accordance with  claim 26 , wherein the knurled surface includes a plurality of ribs having a rib density of 3 to 180 ribs per centimeter. 
     
     
       28. The generator stator core in accordance with  claim 27 , wherein the knurled surface includes a plurality of ribs having a ribs density of 10 to 100 ribs per centimeter. 
     
     
       29. A generator stator core, comprising: 
       a plurality of laminations; and  
       at least two of space blocks extending radially disposed between the laminations defining a ventilation duct therebetween for a fluid to flow through, at least one of the laminations define the ventilation duct includes a plurality of dimples extending into the fluid, the thermal dimples being adapted to impart vortices to the fluid flowing in the ventilation duct.  
     
     
       30. The generator stator core in accordance with  claim 29 , wherein the thermal dimples have a raindrop shape construction. 
     
     
       31. The generator stator core in accordance with  claim 29 , wherein the thermal dimple have a hemispherical shape construction. 
     
     
       32. The generator stator core in accordance with  claim 29 , wherein the thermal dimples are disposed on the at least one of the laminations in a plurality of rows being off-axis to one other.